Journal of Lasers in Medical Sciences

INTRODUCTION: Laser-assisted vaporization of prostate tissue by means of the potassiumtitanyl- phosphate (KTP) laser is in clinical use. Alternative laser sources are available but are lacking clinical experience.The 980 nm wavelength diode laser provides good hemostasis, in addition to a more rapid ablation rate. The aim of this study is approving the capability, feasibility, and good post-operative outcome of vaporization of prostate by means of a diode laser in a long-term follow up.

METHODS: The light (980 nm, 100 W) of a diode laser was transmitted to prostate tissue. The study included 70 men suffering from bladder outlet obstruction due to benign prostatic hyperplasia (BPH). The prostatic lobes were vaporized within the prostatic capsule. Post-operative outcome and voiding were evaluated during a follow-up period of 24 months.

RESULTS: During surgery, no significant blood loss or any fluid absorption occurred. Catheters were removed in the 20.1±4.6 hours. All patients except two were satisfied with their voiding outcome. After removing the catheter, the mean peak urine flow rate significantly increased from 6.8±2.5 ml/s pre-operatively to 15.6±3.1 ml/s postoperatively. No evidence of urgency, dysuria, hematuria, or incontinence was observed. Four patients required re-catheterization, and two of them needed consecutive TURP. After a 1- month, as well as after a 6-month, a 12-mouth, and a 1-year follow-up, all patients were still satisfied with the outcome.

CONCLUSION: This long term experience showed that 100 W-980 nm-diode-laser vaporization prostatectomy was feasible and appeared to be safe and effective for quickly relieving bladder outlet obstruction due to BPH.

INTRODUCTION: Photonics refers to the technology of generating and harnessing light and other forms of radiant energy whose quantum unit is the photon. Photonic technology in the meridian and acupoints research has shown the unique advantages, by which the microcosmic material basis and macroscopic phenomena research can be integrated to interpret the occurrence of propagated sensation along meridian (PSM) and its underlying mechanism. This study seeks to investigate light and heat sensing action along meridian.

METHODS: From the modern research of meridian point of view, PSM is the break point to research the essentiality of meridian. The bio-photonic feature of meridian is the most promising research direction to investigate the PSM phenomena for its contribution to prove the existence of meridian objectively and spontaneously. Therefore, the bio-photonic features of meridian under physiological, pathological, therapeutic, and mechanical conditions were analyzed. Firstly, the four aspects of light sensing action were discussed, i.e. light sensing effect along meridian, blocking effect, laser induced effect and underlying mechanism of light sensing action along meridian. Secondly, the four items of heat sensing action were discussed as well, i.e. thermo-effects, heat perception ability, laser induced heat effect, underlying mechanism on heat sensing effect along meridian.

RESULTS: The authors point out that photonic technology, e.g. ultra-weak luminescence, photonic imaging, infrared imaging and infrared spectrum analysis, biological photons detection and laser Doppler application, can achieve purposes of in vivo, dynamic, multiple comparable studies. Thereby, the effect of light and heat sensing along meridian can be detected and illustrated by the use of natural science. The effect of light sensing and heat sensing along meridians with the help of advantages of photonics is expected to interpret and quantify the meridian doctrine, to provide an important experimental basis for meridians and acupoint properties of light and heat, to find a kind of non-invasive diagnostic technique, and to promote the integration and development of meridians and modern medicine.

CONCLUSION: Light and heat information can be investigated to analyze the relationship between zang-fu organs and meridians, and the functional characteristics of the meridian. Hence, the effect of light and heat sensing along meridian is the break point of the research of photonics in meridian, which is beneficial to further study the meridian optics.

INTRODUCTION: Thermal changes in laser assisted root canal therapy with the use of diode laser can predispose tooth structure to the fracture. This study evaluated the changes in flexural strength of dentin blocks after diode laser irradiations (810 nm).

METHODS: A total of 60 dentinal blocks were prepared from freshly extracted teeth in three different thicknesses (300, 500 and 1000μm) and 20 sections in each of these thicknesses were divided randomly to the test and control groups. Samples in the test groups were irradiated at 2W power setting by scanning movement of 2mm/s of diode laser, and the controls were stored in normal saline. The flexural strength of samples was evaluated by UTM (Universal Testing Machine). Data analysis was done with the SPSS Software 11.5.

RESULTS: Samples of 300μ had the lowest flexural strength (mean: 71/65 mpa) followed by 500 (116.64 mpa) and 1000μ (217.56 mpa). Statistical analyses showed that after laser irradiation, the flextural strength in the samples of 300μ was significantly lower than that in the other groups (500μ, 1000μ) (P= 0.017).

CONCLUSION: Within the limits of this study, diode laser irradiation in laser assisted root canal therapy has no significant effect on flexural strength of root dentinal walls with the thickness of more than 500μ. Although in areas with critical dentinal width (≤300μ), this setting can jeopardize root micromechanical properties and predispose tooth to the root fracture.

INTRODUCTION: Corticotomy-facilitated orthodontics provides a means for rapidly moving teeth purportedly with little damaging effects to the periodontium and with greatly reduced treatment time. The aim of this study was to enhance the orthodontic tooth movement by reducing the cortical bone layer (resistant to bone re-sorption relative to spongious bone) following Erbium, Chromium doped Yttrium Scandium Gallium Garnet (Er-Cr: YSGG)laser irradiation, without reflection of surgical soft tissue flap.

METHODS: In the present experimental study, 8 New Zealand Male rabbits were the samples for the research. The right first premolar of each rabbit (experiment group) underwent treatment for mesial movement with 75 gram of orthodontic force by using closed Ni-Ti coil spring (Dentaurum®). Coil spring was fixed in the cervical region of first premolars by means of ligature wire and No-Mix composite (Dentaurum®) and also activated to the cervical site of incisors. The left first premolars of the subjects were considered as the control group. Laser corticotomy was performed in anesthetized rabbits. Samples were sacrificed for determination of tooth movement after initiating premolar protraction on the 21th day. The amount of orthodontic tooth movement was assessed by using a metal feeler gauge with the precision of 0.01 mm, between mesial surface of the second premolars and distal surfaces of the first premolars. The statistical package of SPSS (Kolmogorov - Smirnov and ANOVA test) was used for analytical evaluation of the measurements.

RESULTS: The amount of orthodontic tooth movement in the experimental group (mean=1.653±0.34 mm) was significantly (p<0.001) greater than that of the control group (mean=0.936 ±0.28 mm). The innovated laser assisted corticotomies enhanced the rate of orthodontic tooth movement on the intervention side, significantly (p<0.001).

CONCLUSION: The innovated method of laser assisted flapless corticotomy is a useful procedure for reducing treatment time and damage to periodontium. It also eliminates the necessity of more invasive intervention of flap surgery.

INTRODUCTION: The use of lasers for treatment has become a common phenomenon in the medical field. Currently, numerous laser systems are available for dental use. The use of lasers for periodontal treatment becomes more complicated because the periodontium consists of both hard and soft tissues.

METHODS: Related articles were gathered and selected carefully and reviewed. Among the many lasers available, high power lasers such as Carbon Dioxide Laser (CO2),Neodymium-Doped Yttrium Aluminium Garnet (Nd:YAG) and diode lasers can be used in periodontics. The use of these lasers is limited to gingivectomy, frenectomy and similar soft tissue procedures including the removal of melanin pigmentation of gingiva. Recently, Erbium: Yttrium Aluminium Garnet(Er:YAG) and Erbium, Chromium doped Yttrium Scandium Gallium Garnet (Er,Cr:YSGG) lasers are used for scaling, root debridement, cutting, shaving, contouring and resection of oral osseous tissues.

RESULTS: In addition to their surgical applications, low-level lasers such as Er:YAG laser irradiation promotes osteoblast proliferation showing higher and favorable bone tissue regeneration. These findings suggest faster bone tissue healing following periodontal and peri-implant low level laser therapy.

CONCLUSION: Advantages of laser treatment in periodontics are effective and efficient soft and hard tissue ablation with a greater hemostasis, bactericidal effect, minimal wound contraction, faster bone tissue healing, minimal collateral damages along with reduced use of local analgesia.

It is of utmost importance to make children interested in and willing to use dental services in order to prevent and treat oral diseases. Therefore, pediatric dental practitioners need to learn new technologies such as lasers, in addition to basic principles. Lasers have opened new horizons in the treatment of both soft and hard oral tissue problems in children. The present article describes application of the most commonly used lasers and their advantages and considerations.

INTRODUCTION: definitive treatment of oral leukoplakia is very important because of its recurrences and malignant transformation depending on the location, clinical feature,degree of dysplasia and etiological factors. there are different kinds of treatment for this lesion, but using high power laser has some advantages like less pain, swelling, prevention of metastasis, edema, less bleeding (dry surgery) and infection.

CASE: a 53_year_old man with leukoplakia lesion with moderate dysplasia on the left side of the ventral surface of the tongue was selected for treatment with co2 laser.the average power is set on 6.2 w with frequency of 20 hz. the irradiation mode was non-contact. the entire lesion evaporated by the laser with a 2 mm safety margin.

RESULT: in this case, 80% of lesion had disappeared after 5 weeks and the 20% residual was evaporated again with the same parameters than the first time. no significant clinical differences were seen between the normal and laser-treated tissue.

CONCLUSION: using laser in the treatment of oral lesions has many advantages like selective removal of the affected tissues and minimal damage to surrounding tissue, leading to excellent wound healing with no or minimal scar and good functional results.

INTRODUCTION: The purpose of this case report is to analyze the results of vestibuleplasty around an over-denture based on dental implants to determine the evidence on the effectiveness of laser-assisted surgery and soft tissue management in implant dentistry.

CASE REPORT: The patient in this case report was a 57 year- old male who was completely edentulous, with a mandibular over denture based on 4 standard implants suffering from pain on chewing, and a general discomfort, especially in anterior segment. He received a standard gingival augmentation surgery which failed to create sufficient vestibular depth. A laser-assisted vestibuloplasty was done to make the environment suitable for making a new overdenture.

CONCLUSIONS: There were clinically significant improvements in vestibular depth and peri implant soft tissue situation by laser. Also, bleeding during surgery was well controlled; the patient’s discomfort and pain were less than the first operation done with gingival graft. Based on our clinical data and review of the literature, an evidence-based approach to the use of lasers for the management of soft tissue in oral surgery is necessary. Simply, there is insufficient evidence to suggest that any specific wavelength of laser is superior to the traditional modalities of therapy. However, improved hemostasis and patient’s satisfaction can be considered as advantages of adjunctive laser therapy in some clinical situations like vestibuloplasty.